According to a known structure of some conventional display device, a touch panel or a protective member (hereinafter called the touch panel or the like) is bonded to a display surface of a display panel to integrate the display panel and the touch panel or the like. More specifically, the touch panel or the like is bonded so as to cover an area from the display surface to the front surface of a casing with a sheet-like adhesive material. Such bonding or integration may be called glass bonding in some cases.
A step determined by the thickness of the casing at an opening edge portion thereof is generated at a boundary between the display surface and the opening edge of the casing. Hence, air bubbles may be generated easily in an adjacent area of the step during bonding of the adhesive material. In order to cancel this step, a thick adhesive material is used, or a plurality of adhesive materials is stacked.
There has also been a structure where a backlight unit is mounted on the rear surface of a display panel to which the touch panel or the like is bonded in advance, and a casing covers the display panel from its rear surface so as to house the backlight unit. The casing has a planar part facing a peripheral part of the touch panel or the like and extending parallel to this peripheral part. This planar part is bonded to the peripheral part of the touch panel or the like. This can reduce the used amount of an adhesive material and realize bonding work more simply.
Japanese Patent Application Laid-Open No. 2012-18401 describes a technique intended to slima liquid crystal display device. More specifically, a circuit film connecting a liquid crystal panel and a printed circuit board extends toward the printed circuit board while passing through a space between the inner wall of a molded frame of a backlight assembly and an optical sheet of the backlight assembly. The molded frame has a groove in order to allow the circuit film to pass through the space without being interfered by the molded frame.
Japanese Patent Application Laid-Open No. 2010-60862 describes a technique intended to reduce the width of a bezel of a liquid crystal display device. More specifically, a gate COF (chip on film) is mounted on a liquid crystal panel. The gate COF is housed in a frame surrounding the liquid crystal panel. This frame has an opening area where the gate COF is inserted. Further, a lid is provided to cover the gate COF inserted in this opening area.
The gate COF of Japanese Patent Application Laid-Open No. 2010-60862 is connected to the liquid crystal panel while it is not connected to a substrate corresponding to the printed circuit board of Japanese Patent Application Laid-Open No. 2012-18401. Such connection is called “connection without substrate” or simply, “without substrate.”
Generally, the COF without substrate projects outwardly of a display panel and extends parallel to a surface of the display panel. This results in troublesome work of housing the COF without substrate in the aforementioned casing that covers the backlight unit from its rear surface side, for example. Depending on circumstances, the COF might be caught between the casing and the touch panel or the like.
The catch of the COF may be prevented for example by fixing the COF to the backlight unit with an adhesive member such as tape before attachment of the casing. However, this necessitates additional work, which is not preferable. This also generates the fear of disconnection of a mounting portion due to removal of the tape for disassembly of the display device for repair, for example.
In the aforementioned structure of Japanese Patent Application Laid-Open No. 2012-18401, the circuit film passes inside the backlight assembly. This might generate problems such as local nonuniformity of backlight brightness and leakage of backlight. These problems may also apply to the structure where the groove for passage of the circuit film is formed in the molded frame.
The aforementioned structure of Japanese Patent Application Laid-Open No. 2010-60862 necessitates a complicated shape and a complicated structure for the frame to house the gate COF. This leads to problems such as reduction in yield and cost increase.